Agents for lubricating oils and methods of making the same



. sirable eil'ects noted.

' One object of'the pr on of an improvemenfiagent for engine oilsPatented July 31, 1945 UNITED STATES PATENT OFFH'QE AGENTS FOBLUBRICATING OILS AND METHODS OF MAKINGTHE Sm Herschel G. Smith,Wallingford, and Troy El. Gantre Lansdowne, Pa., asslgnorl to Gulf Oil(losporation, rem],

No Dra.

ttsbnrgh, Pa.,- a corporation oi pplication July 3,, 19%,, M No. 493,896

Claims. (Cilass-saw -ingly serious, due to the trend toward higherciliciency, higher power out-put per unit weight per engine, reductionin the amount of oil employed in the lubrication system 01 the engine,and other conditions which tend to accelerate the deterioratinginfluences on mineral lubricating oil.

Formation of so-called varnishes and sludges on engine surfaces is dueto oxidation or polymerization effects (or both) of the lubricatingoils, as. well as to like efl'ects oi or from products of combustion ofthe fuels, which find their way by leakage into the engine crankcase orother parts 01' the engine.

The presence of these substances is disadvantageous :for many reasons.In particular. the

oil and fuel oxidation products tend to increasei g sticking andproduction of deposits on piston surfaces and in fixed parts of thecombustion chamber. Sludges are formed in the crankcase of the engine,and the rate of corrosion of bearing surfaces is increased, especiallywith hearing alloys of the types now in use.

Petroleum oils intended for use under the severe conditions describedare compounded (almost always) with a mixture of substances eachintended to counteract one or more of-the unde- These substances, whichfall into a wide variety of chemical classifications, are known by thegeneral term "improvement agentsior addition agents. Preparation ofsatisfactory compounded lubricants is a matter of considerablediillculty. Some of the agents are of low potency in that a rather largeamount has to be added to achieve the desired result. Often twoor moreagents are more or less incompatible with each other; and their ratherlow. solubility, in-generai, further adds to the difliculties inpreparin a use lubricant.

nt invention is themwhich can be incorporated in petroleum oils ineilective proportions and which imparts to the oil a plurality oifuncti.

Another object is the provision of such an agent in the form of asolution in petroleum inbricating oils which serves the functions of (1)acting as a negative catalyst to suppress the formation of deteriorationor oxidation 'pucts, such as varnish, sludge and gum, (2) acting asloosening or suspending agent (detergent) to prevent ring sticking, orcoating of metallic surfaces by such reduced amounts of deteriorationproducts as may be formed and (3) acting as a suspending or dispersingagent for retaining very small particles oi solid deterioration orcontaminating materials in the oil; for example, particles ofcarbonaceous matter that find their way into the oil passing the pistonrings which cannot 2 wbiy be made absolutely tight.

Another object is the provision of a new improvement agent. capable of1110213851 the solubility or dispersibility oi other agents, such asstraight soaps or the like, when it is desirable also to add suchcompounds to an oil in which said soaps and like agents arediflicifltly'soluble,

According to this invention, new improvement agents for lubricating oilscapable of 1.: 1:.

these and other objects are prepared i'rom certain allwlated phenols(olefin-phenol reaction products) bysimultaneously reacting phosphorustrichloride (P011) and phosphorus mt (P483) with the alkylated phenolsto form complex acid reaction products which, in turn, are treated withlime .(or other metal oxide or bydroxide) producing stablemetallo-compounds of alblated phenol esters of phosphorus acids oi thecharacter described in more detail below. That is, as shown post, thenew agents are preparedirom' alkylated phenols containing at least onebranched-chain alkylgroup. Likewise, as there shown, inpreparlng our'newagents, such alkylated phenols are simultaneously reacted withphosphorustrichloride and phosphorus sesquisulflde under controlled conditions toproduce acid reaction products thereof, and the acid reaction productsso obtained are heated with polyvalent metal oxides or hydroxides untilstable,

substantially neutral metallo derivatives thereof are obtained, thestable oil-soluble improvement agents so obtainedbeing separated fromthe unreacted metal oxides and hydroxides and other insoluble compounds.The polyvalent metal compounds so obtained, particularly the diandtrivalent compounds and mixtures thereof, are useful and advantageousfor the present purposes.

bricants: (1) by virtue of its combined metal (e.

g. calcium, etc.) suspending or detergent properties are imparted, aswell as resistance to ring sticking; (2) the combined phosphorus impartsanti-bearing-corrosion and anti-ring sticking properties, as well aspressure carrying properties; (3) the combined sulfur serves to givepressure carrying properties to the oiland to retard corrosion of alloybearings and (4) by virtue of the organic nucleus, the alkylated phenylgroups carrying at least one branched chain alkyl group, the improvedoil has good antioxidant and oiliness properties and suspending andsolubili'zing characteristics.

Thus, according to the invention, there is provided a compound which,dissolved in the oil, imparts thereto all the many desirable featureswhich we wish to obtain, including the several advantages, virtues andproperties described ante. Further, our new improvement agents are sosoluble in motor oils of all types and degrees of refinem'ent that wecan incorporate them in any desired proportions to form a clear solutionin lubricating oils, even in the most highly refined and most parafilnicof the heavy aviation oils, such as are specified in the most severe andexacting aviation services.

. It is known that highly paraifinicpils, refined tothe high degreedesired to secure such desired properties as low carbon-forming effectsand high the way of ready solubility in the oils and the 1 otheradvantageous efi'ects mentioned above. We

can employ very highly refined parafllnic-type aviation oils that havethe desired superior physical characteristics as regards theseparticular properties, and, at the-same time, avoid any undesirableeffects whatever from the use of such oils. In other words, the additionof our compound, which is soluble in the heavy highly refined parafilnicoils, enables us to secure all the properties desirable in the way ofthe oils of superior performance characteristics, as well as the effectsof detergency, avoidance of ring sticking, varnish formation, sludgeformation and corrosion of alloy bearings that might otherwise, beencountered, as well as secure the desired eflect of retarding oxidationdue to the use of more highly refined oils of less tendency to oxidizecombined with the use of a compound which actually retards oxidation.

Another important field of utility for the invention is inDiesellubricating oils. Heretofor'e, it has been considered best to usenaphthene-type oils dosed with certain compounding agents which are ofundesirably low efllciency and which, moreover, are not readily solubleeven in. the'mo'st naphthenic type -of Coastal oils. Thus it has oftenbeen necessary to make a compromise even for the Coastal oils of greatersolubility effect for compound agents between the degree of refining andthe solubility'eflect for the addition agents.

It is quite unsatisfactory for most of these agents as all or part ofthe addition agents heretofore used will often separate from the oilupon standing. For these reasons Diesel lubricating oils hithertoprepared have been rather unsatisfactory, in that they employ low gradeoils of less degree of resistance to oxidation than would otherwise bedesirable. with the present invention, we'prepare an improved oil whichperforms satisfactorily in Diesel engines, employing a highly refinedparaffin-type of oil with control of ring sticking effects and sludgeformation and detergency effects by the incorporation of the presentcompound in any desired proportion.

The new improvement agent has another important advantage in that, inaddition to being very oil-soluble itself, it acts to disperse inmineral oils other improvement agents which are of themselves relativelyinsoluble. For example, in accordance with the present invention, oneper cent or more of calcium oleate or aluminum stearate can be dispersedin mineral oil to form a stable and permanent dispersion with the aid ofan equal quantity of the new agent. Thus, the new agent is sometimesuseful when and where its own antioxidant and dispersing properties arenot required for its value in dissolving other agents.

The new agent is conveniently prepared in the form of a concentrated oilsolution which can ,readily be stirred into an oil to prepare awcompoundlubricant. In preparing the new agent, the

base material is advantageously alkylated phenols which themselves havego'od antioxidant properties. A convenient source for this base materialor principal reactant is the phenol-olefin reaction products prepared asdescribed in U. S. Patent 2,149,759, issued March 7, 1939, to Troy LeeCantrell. For instance, an advantageous material is a heart-cut of suchphenol-olefin reaction products, prepared from the 20-80 per cent cutseparated by steam or vacuum distillation; vacuum distillation beingpreferred. This heartcut is a mixture of liquid, semi-liquid andcrystalline alkylated phenols. It is soluble in all proportions inlubricating oils and gasoline, and soluble in most organic solvents andinsoluble in water and vNaOH solutions. It has the followin properties:

Gravity: A. P. I e 18.0-24.0

Sp. Gr., 60/60 F 0.94650.9100

' Viscosity, S. U. V.: 100 F -61-l00 Pour: F -30 to +15 Color, N. P. Aa- 1.0-1,5 Free phenol: per cent Nil Mineral acidity: per cent:

S03 equivalent Nil Distillation, AS'IM D 86-40: 5

' Over point: F 375-380 End point: F 525-540 10 per cent at: F 415-450 aThis phenol-olefin reaction product contains 65 varying amounts of4-tertiary-butyl phenol, 2-

tertiarybutyl-4-secondary-butyl 'phenol, 2,4-ditertiary-butyl phenol,2,6-dirtertiary-butyl-4-secondary-butyl phenol, 2,4,6tri-,tertiary-butylphenol, 2.6-di-tertiary-butyl-4-methyl phenol,4,6-di-tertiary-butyl-2-methyl phenol, 4,0-ditertiary-.butyl-Z-methylphenol, and other al.-' kylated phenols containing a branched chainalkyl group attached to the phenyl nucleus there- 01'. All thesealkylated phenols have good, antioxidant pmperties and are useful inmaking our new improvement agents. As a class they may be represented bythe following genericformula wherein R, R and R" represent hydrogen oran alkyl group, at least one branched chain alkyl group being present.Those containing secondary or tertiary alkyl groups are particularlyadvantageous for the present purposes.

In proceeding in accordance with the first stage of the presentinvention, such alkylated phenols are brought into reaction withphosphorus-trichloride and phosphorus sesquisulfide phenols, phosphorustrichloride (P013) and phosphorus sesquisulfide (P483), may be variedand controlled to produce reaction products advantageous for the presentpurposes. Usually we employ to 40 parts of phosphorus trichloride and0.1. to 10.0 parts ofphosphorus sesqulsulfide per 100 parts of thealkylated phenol. The acid reaction products so obtained readily reactwith metal oxides and hydroxides, forming metal salts of these alkylatedphenol esters.

. In forming such metal salts, the acid reaction products or estersdescribed ante may be heated with various polyvalent metal oxides andhydroxides, the reaction mixture being heated to temperatures between300 and 450 F. until stable, substantially neutral, oil-soluble nietalloderivatives of said acid reaction products are obtained. During thisheating complex reactions occur and the acid reaction products or estersare converted into stable, neutral,.oil-soluble metallo compounds whichare useful as' improvement agents in mineral oils and oil compositionand are stable under the service conditions usually encountered bycommercial lubricants. That is} this heating in the presence of metaloxide or hydroxide stabilizes the improvement agent at the time it isformed.

After the reaction is complete, any excess metal oxide or hydroxide andinsoluble by-products are separated from the improvement agent bysettling, filtration or other suitable method. Usually these oil-solublemetallo compounds or improvement agents, with or without dilution withmineral oils, are filtered to remove insoluble materials. The filtratesare then ready for use in accordance with this invention.

For instance, valuable improvement agents are readily obtained byheating such acid reaction products or esters with lime. In doing so,lime (quick or hydrated) is added in the proportions of about 10 toparts (figured on CaO) per 100 parts of reaction products and themixture heated at a temperature of 325 to 400 F. for about 5 hours. Thereaction mixture is filtered and isready for use. By adding mineral oilto the above reaction mixture prior to the heating, concentratedsolutions of the improvement agent in oil can be directly obtained uponfiltering out the insoluble material.

In lieu of ordinary lime, dolomitic limes, magnesia or magnesiumhydroxide can be employed. Likewise, other polyvalent metallic oxides orhydroxides, such as alumina or zinc oxide may be employed in preparingour metallo-derivatives' or metal salts of these alkylated phenyl estersof phosphorus acids. That is, various metal com- Pounds may be'employedin the practice of this invention.

The improvement agents so obtained are of complex constitution, evenwhen a single alklated phenol, such as 2,6-di-tertiary-butyl-e-methy1phenol, etc., is employed. Further, using mixtures of alkylated phenols,such as the heartout of the olefin-phenol reaction products describedante, mixtures of metallo-derivatives of alkylated phenyl esters areobtained. As stated, these are advantageous in the practice of thisinvention. A

That is, our improvement agent is probably a mixture of similar oranalogous compounds and may contain varying proportions of the severalconstituents, namely combined phosphorus, sulfur, metal, etc., combinedin a complex metallo compound. As a matter of fact, we vary the relativeproportions of the, reactants, depending upon the particular propertiesdesired. There is considerable flexibility in the proportion of calciumor other metal added and combined for securing a range of detergency,anti-ring sticking, and solid suspension effects; or in the amount ofcombined phosphorus as required to obtain the desired anti-ring stickingand anti-corrosion effects. That is, these constituents of ourimprovement agents can be varied at will. For instance, the metalco'ntentcan be made to vary over relatively wide limits.

That is, in practice we vary the proportions of the several reactants inaccordance with the particular properties desired. After the desiredcombinations have been effected, the reaction product is filtered toremove insoluble compounds and is then ready for use. The filteredmaterials are readily soluble in lubricating oil.

In preparing improved lubricants, the optimum proportion of the agent tobe introduced into lubricating oils depends on the severity of theservice conditions and the degree to which the oil itself tends to formgum or varnish. Ordinarily, from 0.1 to 5.0 per cent by weight of theimprovement agent on the oil is suitable. The improved lubricants soobtained have the advantageous properties described ante and aresuperior lubricants.

The preparation and use of our improvement agents is further illustratedin the following illustrative examples which are typical but notlimitative of this invention.

Erample 1.-In this specific example illustrative of one advantageous wayof preparing an agent within the purview of this invention, 1238 poundsof the above described phenol-olefine reaction product were heatedtol00-120" F. in a stirring still and 412pounds of phosphorustrichloride and 4.5 pounds ofphosphorus sesquisul-- fide were graduallyadded with stirring. After 5 hours at this temperature, the temperaturewas gradually raised and held to MO-420 F. for a of alkylated phenylesters of phosphorus acids and had the following properties:

Gravity 9.0 Viscosity, S. U. V.: 100 F 560 Color, N. P. A 1.75Phosphorus: percent 5.92 Chlorine: per cent 7.60

It readily reacts with metal oxides and hydroxides forming metalderivatives.

In forming stable substantially neutral calcium derivatives thereof,1200 pounds of the above reaction product were heated with 222 pounds oflime in water at 170 F. The mixture was then gradually heated to 325 F.and

. maintained at this temperature for five hours. The resulting productwas cooled to 250 F. and

filtered to remove excess lime and other insolubles.

The calcium treated product so obtained had the following properties:

Gravity: A. P. I 11.2 Viscosity, S. U. V.: 210 F 150 Ash as sulfate: percent". 8.3

This mixture was agitated and heated to 350 F. for 5 hours. The solutionof improved agent in oil so obtained was then admixed with a filter aidand filtered. l

The filtrate had the following identified properties:

Gravity: A. P. I. 17.5 Specific gravity, 60/60 FL-.. 0.9497 Viscosity,S. U. V.: I

100 F 235 210 F 44.2 Pour: F Color, N. P. A 2.5 Sulfur, Bz. per cent0.56 Chlorine, Carius: per cent 0.15 Phosphorus, Carius: per cent 2.85Carbon residue: per cent 2.4 Ash as sulfate. per cent i 4.0

improvement agents in making commercial lubricants and can be readilyincorporated and blended with various lubricating oils and bases toproduce commercial lubricants.

These concentrates can also be prepared with' advantage by incorporatingmineral oil with the acid reaction product prior to reacting the samewith the metal oxide of hydroxide. One such advantageous embodiment ofthis invention is illustrated in the following example:

Example 2.In this specific example illustrati e of another advantageousway of preparing. our improvement agents, 880 pounds of the abovedescribed phenol-olefin reaction product were heated to 100-120" F. and10 pounds of P4s3 and 274 pounds of PCla were gradually added. Afterfive hours atthis temperature, the temperature was gradually raised andheld at 450 F. for a period of 18 hours. v

The reaction product so obtained was a mixture of alkylated phenylesters of phosphorus acids and had the following properties:

Gravity: *;A. P. I 11.0 Specific gravity, 60/60 F; 0.9930 Viscosity, S.U. V.: 100 F 530 Color, N. P. A 1.75 Sulfur, Carius: per cent 1.25Chlorine, Carius: per cent 8.6.0 Phosphorus: per cen 5.91

This reaction product was diluted with approximately an equal weight ofmineral lubricating oil, namely, a Texas oil having a Saybolt viscosityof 104 at 100 F.- The mixture containiii) ing 500 pounds of the reactionproduct and 500 pounds of mineral oil was stirred in an open iron vesseland 74 pounds of hydrated lime added. J r

cating oils; it being a concentrated solution of the effective agent inoil.

By addingvarying proportions of this concentrate to commerciallubricating oils, a wide range of improved lubricants is readilyobtained.

In the foregoing examples,- other polyvalent metal oxides or hydroxidesmay be employed in lieu of lime and other polyvalent metal saltsobtained-which are likewise excellent improvement agents for minerallubricating oils. They too are readily soluble in both pa'raifinic andnaphthenic oils and can be readily incorporated and blended with alltypes of commercial lubricating oils to obtain improved lubricants. Thepreparation of such improved lubricants is further illustrated in thefollowing examples:

Example 3.-An improved lubricating oil was prepared by dissolving 1 percent of the preparation of Example 1 in a high grade lubricating oil foruse in Diesel engines.

Example 4.An' improved lubricating oil was prepared by dissolving 2 percent of the preparation of Example 2 in a high grade lubricating oil foruse in Diesel engines.

The viscosities and conventional identifying characteristics of theseimproved lubricating compositions, together with those of the base oil,were as follows:

In order to evaluate their tendency to preventv ring sticking inengines. these compositions were subjected to a motor test in thelaboratory, using a standard Waukesha'-CFR crankcase with special L headtype cylinder block, coupled to a cradle-type electric dynamometer. Thisengine has a bore of 3% inches, a stroke of 4 /2 inches, and acompression ratio of 4.7:1. The piston is of cast iron with.fourcompression rings and one oil-control ring, all located abovev thewrist pin Three liters of the oil to be tested are placed in thecrankcase. The engine is then run at 900 R. P. M. with the spark and theair-fuel ratio adjusted to give maximum power, and the coolanttemperature is maintained at 350 F. At the end of 25 hours running, theengine is stopped and dismantled and the piston is examined. Theperformance of the oil is then rated according to the condition of thepiston, in keeping with the following scale, in which the rating numberincreases as the piston condition becomes worse:

Ratings In the above test the rating of the several com.. positions wereas follows:

Improved oil Composition Base Example 3 Example 4 Rating No 4 2 1 Thesecompositions were the well known Almen and Timken lubricating test withthe following results:

' Improved oil Composition Base 01 Example 3 Example 4 Almen test,pounds. 6 18 24 Timken test, ..do 14 20 30 Similar improved results areobtained with lubricating oils containing small amounts of otherpolyvalent metal salts of these esters of alkylated phenols.

While the improvement agent of the presentinvention has been describedin reference to compounding engine lubricating oils for the primarypurpose of preventing ring sticking, its field of Usefulness is notconfined to that applialso subjected to the 7 agent for lubricatingoils, from alkylated phenols stuck, and no heavy hard deheated with thesaid cation. It can be used in oils wherever its properties may bedesired. Sometimes it is used for its dispersive powers on other agents,when its own antioxidant and detergent properties are not needed.

That is, another important advantage of the agents of the presentinvention is that in addition to being highly soluble in oilsthemselves, they are effective to disperse in mineral oils certain soapswhich are of themselves diificultly soluble, for example, calcium oleateor aluminum stearate. Again, sulfurized sperm oil soap'is a desirableaddition agent to oils, but its low solubility prevents incorporation ofmore than a rather small quantity in paraifin base oils. By

the present invention 1 per cent or more of such soap can be dispersedin oil, to form a stable dispersion by including an equal amount of thenew improvement agents of this invention. Thus in the practice of thepresent invention, our new agents may be used in conjunction with otherpreviously known addition agents, in compounding lubricating oils toimprove their properties. Thus in the practice of the present invention,various embodiments thereof may be employed in addition to theillustrative embodiments shown ante.

' metal compound per phorus sesquisulfide,

What is claimed is: 1. A process of preparing an improvement containingat least one branched chain alkyl group, which comprises heating partsof said alkylated phenols with 10 to 40 parts of phosphorus trichlorideand 0.1 to 10 parts of phosphorus sesquisulfide, by weight, attemperatures between 300 and 540 F. until substantially all of thephosphorus trichloride and phosphorus sesquisulfide have reacted andacid reaction products thereof are obtained, and converting the acidreaction products so Obtained into stable, substantially neutral metalderivatives thereof by further heating said acid reaction products witha reactive metal compound or a class consisting of the oxide andhydroxides of a polyvalent metal, the amount of said reactive polyvalentmetal compound being suflicient to neutralize the acidity of saidreaction products, and the mixture being heatedto temperatures between300 and 450 F. until stable, substantially neutral metal derivativesthereof are obtained, and separating the unreacted metal oxides andhydroxides and other insoluble compounds from the oil-solubleimprovement agent so obtained.

z. The method of claim 1 metal compound is lime.

3. The method of claim 1 wherein said reactive metal compound is adivalent metal compound.

4. The method of claim 1 wherein the alkylated phenols employed as thestarting material are phenol-olefin reaction products comprising a mix-'ture, of allsvlated phenols containing secondary and tertiary alkylgroups.

5. The method of claim 1 wherein the said acid reaction products of thealkylated phenols are polyvalent metal compound in proportions of 10 to30 parts of the reactive metal compound per 100 parts of said acidreaction products.

6. The method of claim 1 wherein said acid reaction products are dilutedwith mineral oil prior to the treatment with the said polyvalent metal.compounds, and wherein the oil solution of stable, substantiallyneutral oil-soluble metallo compounds so obtained are filtered to removeunreacted metal oxides and hydroxides and other insoluble compounds.

7. A process ofpreparing an improvement agent for lubricating oils, fromalkylated phenols containing at least one branched chain alkyl groupwhich comprises heating 100 parts of said alkylated phenols with 10 to40 parts of phosphorus trichloride and 0.1 to 10 parts of phos- 'byWeight, at temperatures between 300 and 540 F. until substantially allof the phosphorus trichloride and. phosphorus sesquisulfide have reactedand acid reaction products thereof are obtained, diluting the acidreaction product so obtained with mineral oil, adding to the so fluxedacid reaction products a reactive metal compound of the class consistingof the oxides and hydroxides of a polyvalent metal in proportions of 10to 30 parts of said reactive 100 parts of said acid reaction products,further heating the mixture to temperatures between 300 and 450 F. untilstable, substantially neutral, oil-soluble metallo derivatives thereofare formed in situ in the mineral oil, and filtering the oil concentrateof the improvement agent so obtained'to remove unreacted wherein saidreactive pounds insoluble in the oil.

8. An improvement agent soluble in petroleum oil and capable ofinhibiting formation of gum, varnish and sludge in engines, comprisingthe stable, oil-soluble, substantially neutral metallo compoundsobtained by the process of claim 1.

9. An improved lubricating composition comprising a major amount of amineral lubricating oil and a small proportion of the stable,oilsoluble, substantially neutral metallo compounds obtained by theprocess of claim 1, the amount of said oil-soluble improvement agentbeing sufllcient to inhibit the formation and deposition of gum, varnishand sludge in engines and to disperse such deposits when present. 10. Animprovement agent, for lubricating oils,

comprising the stable, substantially neutral prodnot of the process ofclaim 7, said product being readily soluble in petroleum oils andcapable of inhibiting formation of gum, varnish and sludge in engines. 7

HERSCHEL G. S\MI'I'H. TROY L. CAN'I'RELL.

